DFSRMIG and the Connection Gremlin

Ned here again. I recently came across a peculiar SYSVOL migration behavior with DFSR, and I thought I’d fill you in so you don’t chase your tail on this someday.

The Scenario

You can migrate Windows Server 2008 SYSVOL share from using legacy FRS to DFSR. You begin the migration by replacing or upgrading your old DCs with Windows Server 2008. Next, fire up DFSRMIG.EXE, and go to town using our migration guide. It’s simple and straightforward.

You should check your progress at each stage of the migration. It may puzzle you to find this little gem in your event log after the Prepared of the migration (using dfsrmig.exe /setglobalstate 1):

Oh snap, that doesn’t look good. So you run a DFSR Diagnostic health report and see:

Errors:“No connections exist for Domain System Volume.”

Server Details:“No connections exist for Domain System Volume. Affected replicated folders: All replicated folders on this server. Description: The DFS Replication service has detected that there are no connections configured for replication group Domain System Volume. No data for this replication group is being replicated to or from this server. Event ID: 6804 Last occurred: Wednesday, May 20, 2009 at 10:54:56 AM (GMT-5:00) Suggested action: To resume replication, create connections using the DFS Management snap-in or the Dfsradmin.exe command-line tool.”

Ack! You’ve checked replication by creating a test file in the new replicated SYSVOL_DFSR folder. To your surprise; the file replicates to all the DCs. That’s not possible though, as without connection objects there’s no way for DFSR to replicate anything. And, for extra weirdness, not all of the DCs report this issue – even DCs you know have direct replication partnerships with DCs that report the issue.

What the heck is happening?

The Cause

There are actually two things going on here:

1. A 6804 warning event is actually an expected entry under some circumstances, based on AD replication convergence. During creation of a new customer Replication Group you can see this event as well. So that’s no big deal.

Unfortunately, this event does not appear when migrating SYSVOL due to an issue with the DFSR migration code.

The Solution

So the solution I give you here is an easy one that anyone can implement – just ignore it. 🙂 This event is harmless long as:

1. The 6804 event only occurs during a SYSVOL migration.

2. It only happens once.

3. And, it only references the Domain System Volume replication group.

If you want the diagnostic health report event to go away, simply restart the DFSR service on any DCs reporting the event. You won’t see it again. Or don’t restart the service – it’s perfectly ok to ignore the event here too.

We’re looking into a more permanent solution for this, of course. But I figured you’d rather read it here first rather than opening a support case to be told ‘yes, we know’.